各向异性激光介质热效应分析

The Research of the Thermal Effects in Anisotropic Laser Crystals

摘要: 从固体激光器的实际工作条件出发，建立了各向异性立方晶体温度场分布模型，提出各向异性立方激光介质热方程的解析解。并将该结果应用到Nd:YVO₄激光介质中，结果表明：随着泵浦功率密度的增加，晶体的热透镜效应随之增强，热致形变所产生的热透镜效应在Nd:YVO₄晶体中起主导作用。晶体长度-浓度积为固定参量时，晶体热焦距变化趋势不变，但在此种情况下，适当降低晶体掺杂浓度或者增加晶体长度，可以有效地减小晶体内的温度梯度，进而缓解激光晶体热效应。

Abstract: The thermal effects model of anisotropic slab crystal was built based on the practical operation condition of the solid-state laser. The analytical solution of the heat equation for an anisotropic cubic cross-section solid-state crystal is presented. And then the expressions that are reported were applied to a slab Nd:YVO₄ crystal. And the results showed that thermal lens effect enhanced with the increase of the pump power density. Thermal deformation produced by thermal lens effect play leading roles in Nd:YVO₄ crystal in this time. When the product of crystal length and doping concentration was a constant value, the thermal focal length kept basic consistent. However, the slab laser crystal should be decreased doping concentration or increased crystal length moderately in order to relieve the thermal effects.